In a solar cell device including a silicon substrate, a first electrode containing a major proportion of silver and a second electrode containing a major proportion of aluminum are formed on one main surface thereof, i.e., the back surface. The second electrode is connected to the first electrode such that portions of the second electrode overlap the first electrode. In these overlapping portions, silicon readily forms an alloy with silver and aluminum. If some silicon is alloyed, voids occur in portions of the silicon substrate, and the silicon substrate is fragile near the voids. The silicon substrate, which has become thinner recently, readily cracks from these fragile portions. To solve this problem, for example, there is a need for the optimization of the electrode pattern of the first electrode in order to control the overlapping regions of the first and second electrodes (see, for example, Japanese Unexamined Patent Application Publication No. 10-144943).